Method and device for testing tensile properties of a spring rod

Abstract

The application discloses a spring pull rod tensile property testing method and device, which comprises the following steps: installing a tensile property testing device on an upper connecting head of a tension testing machine and fixing the same by using a pin; connecting upper and lower end heads of the spring pull rod in the tensile property testing device and fixing the same by using a pin; setting a program, and the testing machine is stretched upwards to detect a load value under a fixed elongation; the spring pull rod tensile property testing special device comprises an upper connecting device and a lower connecting device; the friction force of a nut and a connecting head of the testing machine can be increased by rotating and tightening the nut, the device and the connecting head of the testing machine can be tightly combined without loosening, and the accuracy of test data is ensured. The method is simple and easy to implement, the test device can reduce the influence on the measurement result, and the installation operation is simple.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of material detection, testing and failure analysis, and relates to a spring rod tensile property testing method and device, in particular to a method and device for detecting the load of a spring rod under a certain elongation. BACKGROUND

[0002] Elastic deformation is that external force overcomes the interatomic force to change the atomic spacing, and the elastic deformation is restored when the interatomic force forces the atoms to return to their original positions. When the metal is elastically deformed, there is a linear relationship between stress and strain, that is, it conforms to Hooke's law. The spring rod testing principle is the analysis of the force of the spring in the spring rod in the proportional elongation stage, that is, the proportional linear relationship according to Hooke's law is used to measure the load value under a certain elongation. When measuring the load of the spring rod under a certain elongation, the displacement starting point of the testing machine is generally taken as zero to start recording, but the structural gap and device gap of the testing machine are introduced, which affects the accuracy of the detection result. The commonly used spring rod tensile property testing device is a straight connection type device designed according to the shape of the testing machine connector and the end of the spring rod. The device has high shape and size requirements. If it cannot completely fit or is damaged with the testing machine connector, the accuracy of the load measurement under small elongation will be affected. SUMMARY

[0003] The purpose of the present application is to provide a spring rod tensile property testing method and device, which aims to solve the problem of load detection of the spring rod under a certain elongation.

[0004] In order to solve the above technical problems, the technical scheme of the present application is as follows:

[0005] A spring rod tensile property testing method, comprising:

[0006] Step one, put the upper connecting device into the upper connector of the tensile testing machine, connect the upper connecting device and the upper connector of the tensile testing machine by passing a pin through the base of the upper connecting device and the upper connector of the tensile testing machine;

[0007] Step two, put the lower connecting device into the lower connector of the tensile testing machine, connect the lower connecting device and the lower connector of the tensile testing machine by passing a pin through the base of the lower connecting device and the lower connector of the tensile testing machine;

[0008] Step three, process external threads on the outer wall of the upper connecting device, set a tightening nut, assemble the tightening nut to the upper connecting device through threads, rotate the tightening nut by means of the auxiliary hole on the tightening nut, so that the tightening nut is in close contact with the end face of the upper connector of the testing machine, thereby fixing the upper connecting device and the upper connector of the testing machine without loosening; the lower connecting device is connected to the lower connector of the testing machine in the same way;

[0009] Step four, the single ear of the upper end of the spring pull rod is connected with the fork ear of the upper connecting device by a pin;

[0010] Step five, set the initial force value, test speed and test termination point of the tensile testing machine program;

[0011] Step six, set the load limit and stroke limit of the tensile testing machine;

[0012] Step seven, zero the load of the testing machine before connecting the lower connecting device with the spring pull rod;

[0013] Step eight, adjust the displacement of the testing machine crossbeam so that the double ear of the lower end of the spring pull rod is matched with the single ear of the lower connecting device, and then connect them by a pin;

[0014] Step nine, first move the testing machine crossbeam upward, stop when the spring pull rod is stretched to the preset value, then slowly move the testing machine crossbeam downward until the force value displayed is 0N, at this time, zero the displacement of the testing machine;

[0015] Step ten, start the test and record the load value of the spring pull rod at the specified elongation.

[0016] Further, the initial force value in step five is not more than 5N.

[0017] Further, the test speed in step five is 10-30mm / min.

[0018] Further, the preset value in step nine is 5-15N.

[0019] A tensile property testing device includes an upper connecting device and a lower connecting device:

[0020] The upper connecting device includes a cylindrical base and a fork ear; the bottom of the fork ear has a large-radius chamfer; the connecting part of the base and the fork ear is cylindrical and has external threads, which can be screwed into a tightening nut; both the cylindrical base and the fork ear have through holes, which are connected with the upper connecting head of the testing machine and the upper connecting head of the spring pull rod by pins, respectively;

[0021] The lower connecting device includes a cylindrical base and a single ear; the bottom of the single ear has a large-radius chamfer; the connecting part of the base and the single ear is cylindrical and has external threads, which can be screwed into a tightening nut; both the cylindrical base and the single ear have through holes, which can be connected with the lower connecting head of the testing machine and the lower connecting head of the spring pull rod by pins, respectively.

[0022] Further, the tightening nut is circular, and the inner surface has threads for assembly onto the upper connecting device and the lower connecting device.

[0023] Further, the outer side of the circular ring is uniformly distributed with auxiliary holes, each hole is ° apart, and an auxiliary rod can be inserted to rotate the nut.

[0024] Further, the inner surface thread of the tightening nut has at least three or more pitches.

[0025] Compared with the prior art, the present application has the following technical features:

[0026] The method is simple and easy to operate, and the test device can reduce the influence on the measurement results and is simple to install and operate. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a schematic diagram of a spring rod tensile property testing device;

[0028] Figure 2 is a schematic diagram of the structure of an upper connecting device of a spring rod tensile property testing device;

[0029] Figure 3 is a schematic diagram of the structure of a lower connecting device of a spring rod tensile property testing device;

[0030] Figure 4 is a schematic diagram of the structure of a tightening nut, the structure of the tightening nut in the upper and lower connecting devices being the same;

[0031] wherein 1 is an upper connecting device, 2 is a lower connecting device, 3 is a tightening nut, 1-1 is a base of the upper connecting device, 1-2 and 2-2 are pins for connecting the upper and lower connecting heads of the testing machine, 1-4 is a forked lug of the upper connecting device, 1-5 and 2-5 are pins for connecting the spring rod, 2-1 is a base of the lower connecting device, 2-4 is a single lug of the lower connecting device, and 3-1 is an auxiliary hole in the tightening nut. DETAILED DESCRIPTION

[0032] In combination with the drawings, a spring rod tensile property testing method is provided. The tensile property testing device is installed on the upper and lower connecting heads of a tensile testing machine, pins are used to pass through the holes in the base of the testing device and the fixing holes in the connecting heads of the tensile testing machine, the upper and lower ends of the spring rod are connected in the tensile property testing device, and positioning pins are used to pass through the holes in the end of the spring rod and the holes in the lugs of the testing device. A program is set, the testing machine is stretched upward, and the load value under a certain elongation is detected. The method comprises the following steps:

[0033] Step one, place the upper connecting device 1 in the upper connecting head of the tensile testing machine, and connect it by passing the pin 1-2 through the base 1-1 of the upper connecting device and the upper connecting head of the tensile testing machine;

[0034] Step two, place the lower connecting device 2 in the lower connecting head of the tensile testing machine, and connect it by passing the pin 2-2 through the base 2-1 of the lower connecting device and the lower connecting head of the tensile testing machine;

[0035] Step three, machining external thread on the outer wall of the upper connecting device 1, setting a tightening nut 3, and assembling the tightening nut 3 to the upper connecting device 1 through the thread; by means of the auxiliary hole 3-1 on the tightening nut 3, rotating the tightening nut 3, so that the tightening nut 3 is in close contact with the end face of the upper connector of the testing machine, thereby fixing the upper connecting device 1 and the upper connector of the testing machine without loosening; the lower connecting device 2 is connected with the lower connector of the testing machine in the same way;

[0036] Step four, the single ear piece on the upper end of the spring rod is connected with the fork ear piece 1-4 of the upper connecting device by means of the pin 1-5;

[0037] Step five, setting the initial force value, test speed and test termination point of the tensile testing machine program; wherein the initial force value is not more than 5N, and the test speed is 10-30mm / min;

[0038] Step six, setting the load limit and stroke limit of the tensile testing machine;

[0039] Step seven, clearing the load of the testing machine before connecting the lower connecting device 2 with the spring rod;

[0040] Step eight, adjusting the displacement of the testing machine cross beam, so that the double ear piece at the lower end of the spring rod is matched with the single ear piece 2-4 of the lower connecting device, and then connected by means of the pin 2-5;

[0041] Step nine, first moving the testing machine cross beam upward, stretching the spring rod to a preset value, then slowly moving the testing machine cross beam downward until the force value displayed is 0N, at this time, clearing the displacement of the testing machine; wherein the preset value is 5-15N;

[0042] Step ten, starting the test, and recording the load value of the spring rod under the constant elongation measured by the test.

[0043] In the scheme, the tensile property testing device comprises an upper connecting device 1 and a lower connecting device 2:

[0044] The upper connecting device 1 comprises a cylindrical base 1-1 and a fork ear piece 1-4; the fork ear piece 1-4 has a large-radiused chamfer at the bottom to increase the structural strength; the connecting part of the base 1-1 and the fork ear piece 1-4 is cylindrical and is provided with external thread, which can be screwed into the tightening nut 3; the cylindrical base 1-1 and the fork ear piece 1-4 are both provided with through holes, which can be connected with the upper connector of the testing machine and the upper connector of the spring rod by means of the pin 1-2 and the pin 1-5 respectively.

[0045] The lower connecting device 2 comprises a cylindrical base 2-1 and a single-ear lug 2-4; the bottom of the single-ear lug is provided with a large-arc chamfer for increasing structural strength; the connecting part of the base 2-1 and the single-ear lug 2-4 is cylindrical and provided with external threads, and can be screwed into the tightening nut 3; the cylindrical base 2-1 and the single-ear lug 2-4 are both provided with through holes, which can be connected with the lower connecting head of the testing machine and the lower connecting head of the spring pull rod respectively by means of pins 2-2 and 2-5.

[0046] The tightening nut 4 is annular, and the inner surface is provided with threads for assembling to the upper connecting device 1 and the lower connecting device 2; the outer lateral surface of the annular body is uniformly provided with three auxiliary holes 3-1, each hole is separated by 120°, and an auxiliary rod can be inserted to rotate the nut; during the tightening process of the tightening nut 4, the end surface thereof is in contact with the surface of the upper and lower connecting heads of the testing machine to increase the friction force, so that the upper and lower connecting devices 1 and 2 are tightly fitted with the connecting heads of the testing machine without loosening.

Claims

1. A method of testing the tensile properties of a spring rod, characterized by, The application relates to a spring tension rod test device and a test method thereof. Step one, the upper connecting device (1) is placed into the upper connecting head of the tension testing machine, and the upper connecting device is connected with the upper connecting head of the tension testing machine through the pin (1-2) penetrating the base (1-1) of the upper connecting device and the upper connecting head of the tension testing machine; Step two, the lower connecting device (2) is placed into the lower connecting head of the tension testing machine, and the lower connecting device is connected with the lower connecting head of the tension testing machine through the pin (2-2) penetrating the base (2-1) of the lower connecting device and the lower connecting head of the tension testing machine; Step three, external threads are processed on the outer wall of the upper connecting device (1), a tightening nut (3) is arranged, the tightening nut (3) is assembled on the upper connecting device (1) through threads, the tightening nut (3) is rotated through the auxiliary hole (3-1) on the tightening nut (3), the tightening nut (3) is in close contact with the end face of the upper connecting head of the testing machine, the upper connecting device (1) is fixedly connected with the upper connecting head of the testing machine, and the upper connecting device (1) is not loose; the lower connecting device (2) is connected with the lower connecting head of the testing machine through the same method; Step four, the single ear piece at the upper end of the spring tension rod is connected with the fork ear piece (1-4) of the upper connecting device through the pin (1-5); Step five, the initial force value, the test speed and the test termination point of the tension testing machine program are set; Step six, the load limit and the stroke limit of the tension testing machine are set; Step seven, the load of the testing machine is cleared before the lower connecting device (2) is connected with the spring tension rod; Step eight, the displacement of the testing machine beam is adjusted, the double ear piece at the lower end of the spring tension rod is matched with the single ear piece (2-4) of the lower connecting device, and the double ear piece is connected with the single ear piece (2-4) of the lower connecting device through the pin (2-5); Step nine, the testing machine beam is first moved upwards, the spring tension rod is stretched to a preset value, then the testing machine beam is slowly moved downwards until the force value is 0N, and the displacement of the testing machine is cleared at this moment; Step ten, the test is started, and the load value of the spring tension rod under the fixed elongation is recorded.

2. The spring rod tensile property test method of claim 1, wherein, The initial force value in step five is not more than 5N.

3. The spring rod tensile property test method of claim 1, wherein, The test speed in step five is 10-30mm / min.

4. The spring rod tensile property test method of claim 1, wherein, The preset value in step nine is 5-15N.

5. A tensile property testing apparatus characterized by, The upper connecting device (1) and the lower connecting device (2) are provided. The upper connecting device (1) comprises a cylindrical base (1-1) and a fork ear piece (1-4); the bottom of the fork ear piece (1-4) is provided with a large-radiation chamfer; the connecting part of the base (1-1) and the fork ear piece (1-4) is cylindrical and is provided with external threads, so that the tightening nut (3) can be screwed; the cylindrical base (1-1) and the fork ear piece (1-4) are both provided with through holes, and the upper connecting head of the testing machine and the upper connecting head of the spring tension rod are connected with the through holes through the pin (1-2) and the pin (1-5) respectively; The lower connecting device (2) comprises a cylindrical base (2-1) and a single ear piece (2-4); the bottom of the single ear piece (2-4) is provided with a large-radiation chamfer; the connecting part of the base (2-1) and the single ear piece (2-4) is cylindrical and is provided with external threads, so that the tightening nut (3) can be screwed; the cylindrical base (2-1) and the single ear piece (2-4) are both provided with through holes, and the lower connecting head of the testing machine and the lower connecting head of the spring tension rod are connected with the through holes through the pin (2-2) and the pin (2-5) respectively.

6. The tensile property testing device of claim 5, wherein, The tightening nut (4) is annular, and the inner surface is provided with threads for assembling the upper connecting device (1) and the lower connecting device (2).

7. The tensile property testing apparatus of claim 5, wherein, The outer side of the ring is evenly distributed with three auxiliary holes (3-1), each hole is 120° apart, and an auxiliary rod can be inserted to rotate the nut.

8. The tensile property testing apparatus of claim 5, wherein, The inner surface thread of the nut (4) has at least three or more pitches.

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